gecko/security/nss/lib/softoken/padbuf.c
2013-05-10 17:19:38 -07:00

50 lines
1.5 KiB
C

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "blapit.h"
#include "secport.h"
#include "secerr.h"
/*
* Prepare a buffer for any padded CBC encryption algorithm, growing to the
* appropriate boundary and filling with the appropriate padding.
* blockSize must be a power of 2.
*
* NOTE: If arena is non-NULL, we re-allocate from there, otherwise
* we assume (and use) XP memory (re)allocation.
*/
unsigned char *
CBC_PadBuffer(PLArenaPool *arena, unsigned char *inbuf, unsigned int inlen,
unsigned int *outlen, int blockSize)
{
unsigned char *outbuf;
unsigned int des_len;
unsigned int i;
unsigned char des_pad_len;
/*
* We need from 1 to blockSize bytes -- we *always* grow.
* The extra bytes contain the value of the length of the padding:
* if we have 2 bytes of padding, then the padding is "0x02, 0x02".
*/
des_len = (inlen + blockSize) & ~(blockSize - 1);
if (arena != NULL) {
outbuf = (unsigned char*)PORT_ArenaGrow (arena, inbuf, inlen, des_len);
} else {
outbuf = (unsigned char*)PORT_Realloc (inbuf, des_len);
}
if (outbuf == NULL) {
PORT_SetError (SEC_ERROR_NO_MEMORY);
return NULL;
}
des_pad_len = des_len - inlen;
for (i = inlen; i < des_len; i++)
outbuf[i] = des_pad_len;
*outlen = des_len;
return outbuf;
}